This work entails study of the interaction between adrenal and gonadal steroids and the plasma proteins to which they bind. Specifically, the major effort involves the characterization of the interaction between these steroids and testosterone-estradiol-binding globulin and corticosteroid-binding globulin. We are at present involved in characterization of the proteins, possible role of the proteins in hormone action, and the effect of binding on egress of hormones from plasma.